Marijuana Use Helps Some Patients Alleviate Symptoms of Bipolar Disorder, Finds New Study

A new study conducted by researchers at Harvard Medical School, Tufts University and McLean Hospital has found that marijuana use may help patients with bipolar disorder to alleviate their symptoms.

The study, titled Joint Effects: A Pilot Investigation of the Impact of Bipolar Disorder and Marijuana Use on Cognitive Function and Mood, was published by the journal PLoS One, as well as the National Institute of Health.

“Marijuana is the most widely used illicit substance in those diagnosed with bipolar I disorder”, states the study’s abstract. “However, there is conflicting evidence as to whether marijuana may alleviate or exacerbate mood symptomatology. As bipolar disorder and marijuana use are individually associated with cognitive impairment, it also remains unclear whether there is an additive effect on cognition when bipolar patients use marijuana.”

With this in mind, the current study “aimed to determine the impact of marijuana on mood in bipolar patients and to examine whether marijuana confers an additional negative impact on cognitive function.”

For the study, “Twelve patients with bipolar disorder who smoke marijuana (MJBP), 18 bipolar patients who do not smoke (BP), 23 marijuana smokers without other Axis 1 pathology (MJ), and 21 healthy controls (HC) completed a neuropsychological battery. Further, using ecological momentary assessment, participants rated their mood three times daily as well as after each instance of marijuana use over a four-week period. ”

Results revealed that “although the MJ, BP, and MJBP groups each exhibited some degree of cognitive impairment relative to HCs, no significant differences between the BP and MJBP groups were apparent, providing no evidence of an additive negative impact of BPD and MJ use on cognition.”

The study concludes by stating that “Findings suggest that for some bipolar patients, marijuana may result in partial alleviation of clinical symptoms. Moreover, this improvement is not at the expense of additional cognitive impairment.”

Anthony Martinelli

Anthony is co-founder and Editor-in-Chief of TheJointBlog. He has worked closely with numerous elected officials who support cannabis law reform, including as the former Campaign Manager for King County (WA) Councilmember Dave Upthegrove. He has been published by multiple media outlets, and is a former contributor for Village Voice Media.